The present invention relates generally to road markers and more specifically to an improved base for a road marker which is secured in a recess of the road.
Pavement road markers generally include a base and a light source or reflector on the base. The base is mounted in a recess in the road and held thereto, for example, by epoxy. The bases usually include a reflector support surface and a series of locators or buttons extending from the lateral edge thereof. The bottom surface of the locators engages the top surface of the roadway to position the reflector support surface at a given distance below the top surface of the roadway. The locators are an integral part of the base which is generally a cast of iron material. Such a road marker is illustrated in U.S. Pat. No. 5,454,664 to Siblik.
The road marker of the Siblik Patents includes webs on the bottom to disperse liquid adhesively upwardly over the sides of the base when mounted on the pavement recess. It also includes protrusion 7 to distribute adhesive over the underside of the base when mounted in the pavement recess. Even with these provisions, sometimes additional caulking is required to totally fill the road recess after the marker has been inserted.
One of the problems experienced by all road markers is that they are damaged and/or ejected from the recess in the road surface by continual forces applied by snowplow blades or other snow removal equipment. One source of the problem are exposed edges of the base above the road. One of the first sources are the locators or buttons at the lateral side of the base. Another source is the leading edge of the base which extends above the road surface. Typically, the adhesive epoxy forms a stronger bond with the base than it does with the road. Thus, they move as a unit and the bond between the epoxy and the road is broken. Once this bond is broken, further impact from snowplows or other snow removal devices will eject the road marker from the recess in the roadway.
A road marker base according to the present invention addresses these problems by providing locators or protrusions which are frangible connected to the base. The base includes a bottom surface to be received in a recess in the road and a reflector support surface. The pair of protrusions extend horizontally from the base in opposite directions and transverse to the direction of travel and include a bottom surface for engaging the top surface of the roadway adjacent the recess. The bottom surface defines the height of the reflector support surface relative to the road""s top surface. The protrusions being frangible connected to the base allow any impact received by the protrusions to separate the protrusions from the base. This removes one of the objectionable surfaces.
The frangible protrusions can be the result of the base being of a first hardness and the protrusions are of second hardness less than the first hardness. For example, the base may be made of metal and the protrusions made of non-metal, for example, wood or plastic. The base may be metal of the first hardness and the protrusions may be a metal of the second hardness less the first hardness. Also, the base may be a single unit with the protrusions and the protrusions are connected to the base by a weakened section.
In another embodiment, slots are provided in the base and protrusions are joined to the base in the slots. The protrusions may be discs or other flat elements which are received in the slot and extend horizontally therefrom. In a further embodiment, the protrusions may be an inverted L-shaped having a horizontal and a vertical leg. The vertical leg is mounted to the base and the horizontal leg has the bottom surface which defines the height of the reflector support surface relative to the road""s top surface. The L-shaped protrusion may include a third leg extending from the vertical leg and engaging the bottom surface of the base. The base may include a hole and the L-shaped protrusion includes a post extending from the vertical leg into the hole, thereby mounting the protrusion to the base.
The base preferably includes a pair of horizontally extending protrusions on each side and spaced along the direction of travel. The bottom of the surface of the base includes vertical protuberances adjacent the lateral edges of the bottom surface and extending, in the direction of travel, substantially the length of the pair of protrusions. The bottom surface may also include additional vertical protuberances adjacent the lateral edges of the base and extending in the direction of travel greater than the length of the reflector support surface.
The bottom surface of the base includes a ridge defining a recess and at least one opening is provided through the ridge into the recess. The reflector support surface may also include a wall extending up therefrom and transverses the direction of travel. The wall has a height at least equal to the height of the reflector. Alternatively, the reflector itself may include such a wall.
A method of making a road marker base with a frangible protrusions includes forming a base including reflector support surface. Two openings are formed in opposed surfaces of the base and protrusions, having a bottom surface, are mounted in the openings and extend horizontally from the base. The base and openings may be formed simultaneously, for example, by casting. Alternatively, the openings may be formed by machining the base. The protrusions are preferably bonded in the openings. The protrusions selected to have substantially less than the hardness of the base. A unidirectional base includes a reflector support surface adjacent one end of the base in the direction of travel capable of receiving and providing visibility of both faces of a standard bidirectional reflector.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.